Most people attend to C&P that blog and wrap it in domain ip6 {} if they also want to filter IPv6. This works fine accept for the ICMP part. It only allows echo requests (a normal ping/mtr). But IPv6 does Neighbor Discovery Protocol (the successor of Address Resolution Protocol) via ICMP. Your device won’t be able to reach your gateway without allowing ICMP completely, so a simple C&P will break existing IPv6 setups. My fixed version is: